Freezing apparatus



Filed Feb. 11, 1958 May 29, 1962 e. 'TREPAUD 3,036,443

FREEZING APPARATUS 2 Sheets-Sheet 1 FiG.1

G- TREPA'UD FREEZING APPARATUS May 29, 1962 Filed Feb; 11, 1958 2Sheets-Sheet 2 3,036,443 FREEZING APPARATUS Georges Trpand, 17 RueLegendre, Paris, France Filed Feb. 11, 1958, Ser. No. 714,633 Claimspriority, application France Nov. 28, 1957 5 Claims. (Cl. 62--352.)

The present invention relates to the tubular freezing apparatus in whichthe ice is produced, in the shape of cylindrical tubes or bars, in pipesvertically disposed in an enclosed space in which these pipes bathe in acold-producing fluid: for the withdrawing, the bars of ice are separatedfrom the walls of the freezing pipes by the action of a warm fluid sentin the enclosed space and fall in a collecting container which isusually equipped with a device to cut them into lengths. The tubularfreezing apparatus of this type are divided into two classes: in thefirst class, the freezing is produced by means of a brine cooled in a.separate cold generator, whereas in the apparatus of the second class,referred to as direct expansion apparatusand to which belong theapparatus according to the present invention-to obtain the freezing acold producing liquid such as ammonia or Freon, is evaporated directlyin the enclosed space containing the freezing pipes by means of acompressor and a condenser connected in series with this enclosed space.These apparatus work, either in a flooded state and, in this case, thecold producing liquid fills up, to a given height, the enclosed spacecontaining the freezing pipes, or by injection of the cold producingliquid in the enclosed space where it evaporates. In freezing apparatusworking in the flooded state, the withdrawing of the bars of ice out thefreezing pipes is carried out by forcing, by means of hot gases comingfrom the compressor, the cold producing liquid, out of the enclosedspace which contains the freezing pipes, in a special container. The hotgases coming into direct contact with the outer wall of the freezingpipes bring about the superficial melting of the tubes of ice which isnecessary for the withdrawing. The cold producing liquid placed inreserve, after this withdrawing, is brought anew in the re frigerator.This travelling of the cold producing liquid requires complicated handoperated as well as self acting devices. In addition, the heating of thefreezing pipes, necessary for the withdrawing, is not carried out in ahomogeneous way, as the transmission of the heat is hindered and delayedby the remaining liquid and by a condensation taking place at thesurface of the cold pipes between the wall and the steam. To end, withthis process for the withdrawing, it is necessary to keep the compressorrunning also during the phase of the withdrawing, thus resulting in animportant consumption of energy.

An object of the invention is to provide a process for the withdrawingof the ice, said process being particularly suitable for the tubularrefrigerators Working in the flooded state. A further object of theinvention is the provision of a process for the withdrawing of the ice,which consists in circulating, through the enclosed space containing thefreezing pipes, the cold producing medium in the liquid state which hasbeen previously heated in an exchanger after the stopping of thecompressor.

When compared with the withdrawing by means of hot gases from thecompressor, the advantages of this new process are as follows:

(1) The cold producing machine proper (compressor) works only during thefreezing phase and is stopped during the withdrawing of the ice.

(2) The transmission of heat between the heated cold producing liquidand the wall of the freezing pipes is carried out under very goodconditions and allows to speed up the withdrawing operation.

(3) The calories required for the withdrawing are rates Patent M broughtfrom the outside by a circulation of water, using swans Patented May 29,1962 for instance the water which, in the preceding freezing phase, wasused to cool the hot gases in the condenser of the refrigerator.Besides, on account of the very small specific heat of the liquid Freonused as a cold producing fluid (0.225)., the amount of heat brought intoaction, for instance to bring the cold producing from 8 or 10" to 5 or7, is comparatively small and forms but a small part of the total amountof calories required. In addition, it is possible to recover the coldcontained in the water used to heat the liquid Freon, for instance byusing anew this water in the condenser or by filling up the refrigeratorin the following cycle. a

(4) The equipment requires only a heat exchanger and a circulating pumpfor the liquid 'Freon: besides the exchanger can, in important plants,be constituted by the proper condenser of the refrigerator. The flow ofthe pump must be rather important to secure a fast heating of the Freon,in two or three minutes for instance, with a fall of the temperature ofabout 2 between the inlet and the outlet of the refrigerator, but, onaccount of the reduced loss of head, the consumption of energy necessaryto drive the pump is much smaller than the consumption required in theknown plants, for the working of the compressor during the phase of thewithdrawing. By way of example, two forms of embodiment of a plant forthe working up of the process according to the invention are describedhereafter and schematically illustrated in the annexed drawing.

FIGURE 1 illustrates a plant including a separate exchanger to heat thecold producing liquid.

FIGURE 2 illustrates a plant in which the cold producing medium isheated in the condenser of the freezing machine during the withdrawing;and

FIGURE 3 is a large scale fragmentary sectional view taken on the line3-3 of FIGURE 1.

The proper tubular refrigerator, schematically illustrated in FIGURE 1,is constituted by an enclosed space 1, having for instance an annularsection and in which are mounted pipes 2, 2 in which the water to befrozen circulates during the freezing phase: these pipes are fixed attheir ends in watertight plates 3, 3 and 4, 4' forming, in a known way,two compartments 5, 5 in which the cold producing fluid as no access, toavoid the formation of ice in the ends of pipes 2, 2' which would hinderthe withdrawing of the ice from said pipes. The pipes 2, 2' are, in aknown way, surrounded with metallic sleeves 6, 6 opened at both ends,the working of which shall be described hereafter. The sleeves 6, 6' arefixed at their ends in transverse plates 7, 7. The inper. chamber 8 ofthe enclosed space 1 is connected with two end chambers 9, 9 throughpipings 10, 11, provided with hand valves 12, 13, which will bedesignated hereafter as cocks. The circuit forthe feeding of the machinewith water to be congealed and the devices collecting the ice are notillustrated as these devices are known and do not form a part of theinvention.

The plant includes a coldproducing machine constituted by a compressor14 which sucks the expanded vapours of the cold producing medium in theupper chamber 9 of the refrigerator through a piping 15 provided with acock 16 and forces back these vapours in a condenser 17 connected withthe lower chamber 9 of the refrigerator through a piping 18 providedwith a cock 19 and a thermostatic valve 20, governed by the pressure ofthe gases in the bulb 21, at the outlet of the refrigerator.

According to the invention, the plant includes a heat exchanger 22connected, on the one hand, with the upper chamber 9 of the refrigeratorby the piping 23 provided with a cock 24 and, on the other hand, with apump 25 connected with the lower chamber '9 of the refrigerator by apipe 26 provided with a cook 27: a level balancing pipe 28, providedwith a cock 29, connects directly the central chamber 8 of therefrigerator with the inlet of the pump 25. The exchanger 22 is providedwith a circulation of water 30,30, and this water, can possibly, asabove indicated, be the same as the water used in the condenser, 17 tocool the gases discharged by the compressor 14.

The machine works, as follows: during the freezing, the cocks 12, 13,16,19, are 'open, the cocks 24, 27, 29 are shut off. V r

The feeding of the refrigerator with liquid Freon from the condenser .17is carried out through the thermostatic valve 20: its level reaches forinstance N in the enclosed space 1. On account of the suction of thecompressor, the liquid goes up in the tubular sleeves 6, 6' round thepipes 2, 2' said sleeves securing therebya less tumultuous boiling ofthe liquid'and a better transmission of the cold to thepipes 2.

During the withdrawing phase, the cocks 12, 13, 16, 19 are shut off andthe cocks 24, 27, 29 are open. The compressor 14 is stopped, the pump 25is started and circulates the liquid Freon through the exchanger 22which. is filled up with liquid Freon. The heated \Freon is forced bythe pump 25 into the chamber 9', flows through the tubular sleeves 6round the pipes 2, and heats them up to the upper chamber 9 and flows.from there through the piping 23 to the exchanger. Thanks to the tubularsleeves 6, the liquid Freon forced under pressure from the pump in thelower chamberl9 is uniformly allotted at the inlet of the pipes 2 sothat all these freezing tubes are simultaneously heated.

During the heating phase, the cock'29 connects up the inlet of the pumpwiththe central chamber 8 of the refrigerator in which the level of theliquid Freon comes'in 'N', below N, because a part of the liquid is ateach moment of this phase in the upper chamber 9.

After the withdrawing, when the bars of ice have moved down out-oftherefiigerator, the level of the liquid Freon must be brought back tothe value N necessary for the freezing phase for the reasons givenhereafter: it is sufiicient for that to open the cocks 1 2 and 13 and tostop the pump 25: as all the conduit pipes are then open, the liquidfalls back in a few seconds in the lower part of the circuit so that itbecomes possible to open anew the cooks 16, 19,.to close the cocks 24,27, 29 and to start anew the compressor for the next withdrawing. Theimmediate restoration of a suitable level is of great importance: itavoids, on the one hand, the damages which could result in thecompressor from a stroke of the liquid owing to a time necessary for therestorationof the level by the ace tion of the thermostatic regulator.

As the exchanger-22 is still .full of liquid Freon, it 7 possible, tohave the disposal of some hot Freon for the next withdrawing, which isthereby accelerated, to circulate the heating. water through theexchanger during all the freezing phase or during a part of this phase.The expansion of the liquid Freonis in that case permitted by thecompression of the part of the gas contained in the piping 23, but it ispossible, in case of need, to add an expansion compenser constituted bytight elastic bellows- 31 arranged in one of the ends 32 of theexchanger 22.

In the form of embodiment illustratedin FIGURE], there is no exchanger,and the heating of the Freon for the withdrawing is carried out in thecondenser 17 of the cold producing machine, arranged in this case abovethe level N of the liquid Freon during the freezing phasein'thejinclosed space rat the refrigerator and providedwith acock 33,allowing to isolate it from the compressor 14. The condenser 17isconnected, on the one hand, through the piping 34 provided .with acock 35, with the upper chamber 9 of the refrigerator, and on the otherhand, at its lower part 41 in which the condensed Freon 4 through a pipe36 provided with a cock 37. A piping 38 in which are mounted the pump 25and a cock 39, connects the bottom of the central chamber 8 with thelower chamber 9' of the refrigerator.

During the freezing phase, the Water circulation 40, 40 of thecondense'r'cools down and condenses the vapours forced back by thecompressor whereas, during the withdrawing phase, this water circulationheats the cold liquid Freon which is circulated by the pump 25, throughthe refrigerator as in the former example.

The apparatus works as follows:

During the freezing phase, the cocks 12, 13, 16, 19 and 33 are open, thecocks 35, 37, 39 are closed.

During the withdrawing phase, the compression is stopped, the cocks 12,13, 16, 19, 33 are closed, the cocks 35, 37 and 39 are open and the pump25 is started. The pump sucksthe liquid Freon from the central chamber 8of the refrigerator and forces it into the lower chamber 9', from wherethe liquid rises through the sleeves 6 around the pipes 2 up to theupper chamber 9, passes through the piping 34 in the condenser 17 whereit is heated and flows back, through the duct 36, in the chamber 8of-the refrigerator. The level of the liquid in this chamber 8 decreasesfrom N to N during this phase of the working as this liquid is partly inthe upper chamber 9 and partly in the condenser 17. After thewithdrawing of theice, the stopping of the pump and the opening of thecocks 12, 13, causes instantly the fall of the liquid in the lower partof the circuit and thereby the restoration of the level N, which issuitable for the working in the freezing phase. The starting 'of thenext freezing operation is obtained very simply by shutting off thecocks 35, 37, 39, opening the cocks 16, 33, '19 and starting anew thecompressor;

The automatic working of the plants illustrated in FIGURES l and 2 canbe obtained very simply.

What I claim'is:

l. I In a tubular freezing apparatus operated on alternate freezing andthawing phases, including an evaporating chamber partially filled with aliquid cold producing medium and provided with, freezing tubescontaining the water to. be frozen and arranged vertically therein to berefrigerated in a flooded condition by the evaporation of said liquidmedium during the freezing phase, the provision of a compressorconnected to the upper part of said evaporating chamber to draw thevapors of the cold producing medium therefrom, of a condenser providedwith cold water circulating means and connected to said compressor tocondense the compressed vapors discharged by the compressor and toreturn the condensed cold producing medium to the lower part of theevaporating chamber, of means to heat'said cold producing liquid duringthe thawing phase, said means comprising a heat exchanger, of means tocirculate heating water through said heat exchanger, and of means tocirculate said heated liquid medium through said evaporating chamber tothaw the ice loose from the inner walls of the freezing tubes, saidmeans comprising a pump connected in series with said heat exchanger andsaid evaporating chamber to suck the heated cold producing liquid mediumfrom the upper part of said chamber and to discharge same in the lowerpart thereof, of valve means to isolate the compressor and the condenserfrom the evaporating chamber during the thawing phase and of valve meansto isolate the pump and the exchanger from said chamber during thefreezing phase, of means to circulate the heating water in the heatexchanger during the freezing phase during which 's'aid exchanger isisolated from the evaporating chamber ,to obtain a reserve of hot coldproducing medium for end of the exchanger.

2 In a tubular freezing apparatus operated on alternate accumulates, itis'connected with the central chamber 8 .7 freezing and thawing phases,including an evaporating chamber partially filled with a liquid coldproducing medium and provided with freezing tubes containing the waterto be frozen and arranged vertically therein to be refrigerated in aflooded condition by the evaporation of said liquid medium during thefreezing phase, the pro vision of a compressor connected to the upperpart of said evaporating chamber to draw the vapors of the coldproducing medium therefrom, of a condenser provided with cold watercirculating means and connected to said compressor to condense thecompressed vapors discharged by the compressor and to return thecondensed cold producing medium to the lower part of the evaporatingchamber, of valve means to isolate the compressor from the evaporatingchamber during the thawing phase, of means to heat the liquid coldproducing medium in said condenser, of a pump, and of means forconnecting said pump in series with the condenser to said evaporatingchamber to circulate the heated liquid cold producing medium throughsaid chamber, the condenser being located above the level at which theliquid cold producing medium is maintained in the evaporating chamberduring the freezing phase.

3. A tubular freezing apparatus of the direct expansion type operated ina flooded condition comprising a vertical cylindrical evaporator,perforated transverse partitions arranged near the upper and lower endsof said evaporator, freezing tubes tightly fixed in the perforati-ons ofsaid transverse partitions, means to circulate the water to be frozenthrough said tubes, a second perforated transverse partition arrangednear each end of the evaporating chamber below the first upper partitionand above the first lower partition, thin tubular metallic sleevesarranged coaxially around the said freezing tubes, tightly fitting inthe perforations of said second partition and having their ends freelyopening in the chambers formed between said first and second partitions,a cold producing machine comprising a compressor and a condenserconnected in series between said upper and lower chambers of theevaporator, two pipings provided with valve means and arranged betweenthe central chamber of the evaporator and its upper and lower chambersrespectively, a heat exchanger and a pump connected in series betweensaid upper and lower chambers of the evaporator, valve means to isolateduring the thawing phase the cold producing machine from the evaporatorand to isolate therefrom the pump and the exchanger during the freezingphase, whereby the liquid cold producing medium is circulated throughthe evaporator during the thawing phase, and means to heat in theexchanger said circulating liquid medium.

4. In a tubular freezing apparatus operated on alternate freezing andthawing phases, including an evaporating chamber partially filled with aliquid cold producing in the evaporating chamber through a closedcircuit comprising said heat exchanger, said pump and said evaporatingchamber, whereby the ice bars formed in said freezing tubes during thefreezing phases are superficially melted and thereby separated from theinner walls of said freezing tubes.

5. A tubular freezing apparatus operated on alternate freezing andthawing phases, including an evaporating chamber partially filled with aliquid cold producing medium and provided with freezing tubes containingthe water to be frozen and arranged vertically therein to berefrigerated in a flooded condition by the evaporation of said liquidmedium during the freezing phases, a compressor, a conduit connectingsaid compressor to the upper part of said evaporating chamber to drawthe vapors of the cold producing medium therefrom, a condenser providedwith cold water circulating means, said condenser being connected tosaid compressor to condense the compressed vapors discharged by thecompressor and to return the condensed cold producing medium to thelower part of the evaporating chamber, means to heat said cold producingliquid during the thawing phases, said means comprising a heatexchanger, means to circulate water through said heat exchanger, andmeans to circulate said heated liquid medium through said evaporatingchamber to thaw the ice loose from the inner walls of the freezingtubes, said last named means comprising a pump connected in series withsaid heat exchanger and said evaporating chamber to draw ReferencesCited in the file of this patent UNITED STATES PATENTS 2,387,899 GrunerOct. 30, 1945 2,397,347 Gruner Mar. 26, 1946 2,628,479 Powers et al.Feb. 17, 1953 2,700,280 Heuser Jan. 25, 1955 2,775,098 MacLeod Dec. 25,1956

